﻿<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>验证码输入</title>
<style type="text/css">
	*{
		margin:0;
		padding: 0;
		box-sizing: border-box;
	}
	html{
		width: 100%;
		height: 100%;
		font-size: 16px;
	}
	body{
		width: 100%;
		height: 100%;
		-moz-user-select: none; /*火狐*/ /*禁止用户在页面选择文字*/
		-webkit-user-select: none; /*webkit浏览器*/
		-ms-user-select: none; /*IE10*/
		-khtml-user-select: none; /*早期浏览器*/
		user-select: none;
	}
	.code{
		width: 400px;
		margin:0 auto;
	}
	.input-val{
		width: 295px;
		background: #ffffff;
		height: 2.8rem;
		padding: 0 2%;
		border-radius: 5px;
		border: none;
		border: 1px solid rgba(0,0,0,.2);
		font-size: 1.0625rem;
	}
	#canvas{
		float:right;
		display: inline-block;
		border:1px solid #ccc;
		border-radius: 5px;
		cursor: pointer;
	}
	.btn{
		width: 100px;
		height: 40px;
		background: #f1f1f1;
		border: 1px solid #ccc;
		border-radius: 5px;
		margin: 20px auto 0;
		display: block;
		font-size: 1.2rem;
		color: #e22e1c;
		cursor: pointer;
	}
</style>
</head>
<body>
<br>
<div class="code">
	<input type="text" value="" placeholder="请输入验证码（不区分大小写）" class="input-val" />
	<canvas id="canvas" width="100" height="43"></canvas>
	<button class="btn">提交</button>
</div>

<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript">
$(function(){
	var show_num = [];
	draw(show_num);

	$("#canvas").on('click',function(){
		draw(show_num);
	})
	$(".btn").on('click',function(){
		var val = $(".input-val").val().toLowerCase();
		var num = show_num.join("");
		if(val==''){
			alert('请输入验证码！');
		}else if(val == num){
			alert('提交成功！');
			$(".input-val").val('');
			draw(show_num);

		}else{
			alert('验证码错误！请重新输入！');
			$(".input-val").val('');
			draw(show_num);
		}
	})
})

function draw(show_num) {
	var canvas_width=$('#canvas').width();
	var canvas_height=$('#canvas').height();
	var canvas = document.getElementById("canvas");//获取到canvas的对象，演员
	var context = canvas.getContext("2d");//获取到canvas画图的环境，演员表演的舞台
	canvas.width = canvas_width;
	canvas.height = canvas_height;
	var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
	var aCode = sCode.split(",");
	var aLength = aCode.length;//获取到数组的长度
	
	for (var i = 0; i <= 3; i++) {
		var j = Math.floor(Math.random() * aLength);//获取到随机的索引值
		var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
		var txt = aCode[j];//得到随机的一个内容
		show_num[i] = txt.toLowerCase();
		var x = 10 + i * 20;//文字在canvas上的x坐标
		var y = 20 + Math.random() * 8;//文字在canvas上的y坐标
		context.font = "bold 23px 微软雅黑";

		context.translate(x, y);
		context.rotate(deg);

		context.fillStyle = randomColor();
		context.fillText(txt, 0, 0);

		context.rotate(-deg);
		context.translate(-x, -y);
	}
	for (var i = 0; i <= 5; i++) { //验证码上显示线条
		context.strokeStyle = randomColor();
		context.beginPath();
		context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
		context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
		context.stroke();
	}
	for (var i = 0; i <= 30; i++) { //验证码上显示小点
		context.strokeStyle = randomColor();
		context.beginPath();
		var x = Math.random() * canvas_width;
		var y = Math.random() * canvas_height;
		context.moveTo(x, y);
		context.lineTo(x + 1, y + 1);
		context.stroke();
	}
}

function randomColor() {//得到随机的颜色值
	var r = Math.floor(Math.random() * 256);
	var g = Math.floor(Math.random() * 256);
	var b = Math.floor(Math.random() * 256);
	return "rgb(" + r + "," + g + "," + b + ")";
}
</script>

</body>
</html>